How can I define material properties that depend on solution variables in CFX 11.0?


A user may define material properties that depend on solution variables (e.g. Temperature) by defining a user fuction or a polynomial:

FUNCTION: sh_pol
Option = Interpolation
Option = One Dimensional
Argument Units = [K]
Result Units = [J kg^-1 K^-1]
INTERPOLATION DATA:
Data Pairs =
293.15,400,373.15,401,473.15,402,523.15,403.5,573.15,404,623.15,404.5
,673.15,405
Extend Max = Off
Extend Min = Off
END


and using this function to define density, viscosity, specific heat, thermal conductivity etc. When specific heat is defined as a function, the code creates a table for enthalpy h=f(T). By defaults the table range of temperature is between 100 K and 5000K. Therefore, the function/polynomial that defines specific heat (Cp) has to cover the same range. If the range over which Cp is defined is narrower, than the range has to be included in the definition of material properties:

MATERIAL: material1
Material Group = User
Option = Pure Substance
Thermodynamic State = Solid
PROPERTIES:
Option = General Material
TABLE GENERATION:
Minimum Temperature = 300 [K]
Maximum Temperature = 650 [K]
ENDEQUATION OF STATE:
Density = 870 [kg m^-3]
Molar Mass = 68.0 [kgkmol^-1]
Option = Value
END
SPECIFIC HEAT CAPACITY:
Option = Value
Reference Temperature = 350.0 [K]
Specific Heat Capacity = sh_pol(T)
Specific Heat Depends On = Temperature
END
THERMAL CONDUCTIVITY:
Option = Value
Thermal Conductivity = 500 [W m^-1 K^-1]
END
END


If this is neglected, the code will generate an error massage and stop.
**** Entered By: dsclarke @ 05/09/2007 03:10 PM ****





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